Should I have the opportunity to travel back in time to converse with great philosophers, Hume would be high on my itinerary. My gratitude for his insights and hospitality would surely tempt me to reciprocate by telling him about my time travels1.

But I fear he would not believe me. For the reasoning underlying Hume's famous scepticism about miracles dooms my tales of time travel2 to an incredulous reception. The ensuing paragraphs will be dedicated to an elucidation of this fear.

This elucidation is of more than historical interest, since Hume's reasoning about miracles still strikes many contemporary philosophers as cogent. Thus the scepticism about time travel3 that I attribute to Hume should also be shared by his followers.

It should be noted that the scepticism at issue is epistemological rather than metaphysical. The key question will not be 'Is time travel4 possible?' We shall instead ask whether it is possible to justify a belief5 in a report of time travel6. The metaphysical issue will only be addressed in response to the question of whether one can be an epistemological sceptic about time travel7 without being a metaphysical sceptic.